(a) Technical Field
The present invention relates to a metal layer in a semiconductor device and a method of forming the same. More particularly, the present invention relates to a method of forming a metal layer in a semiconductor device that may prevent canting and falling of a metal line by enhancing adhesion of the metal layer with an insulation layer.
(b) Description of the Related Art
Recently, semiconductor devices have become more highly integrated such that a line width thereof has been reduced to below 0.25 μm, and metal wiring is formed to be very narrow during a manufacturing process of a semiconductor device. As the design rule is decreased, a height of metal wiring is increased while a width thereof is decreased. Usually, a metal line is formed by a sequence of processes such as a metal deposition process, a photolithography process, an etching process, etc. When a metal layer used to form a high height and a narrow width does not have sufficient adhesion to a lower insulation layer, a metal line may cant or fall down on the lower insulation layer during a process such as a wet process, an annealing process, etc., that is performed after the etching of the metal layer.
FIG. 1 shows a conventional method of forming a metal layer. Referring to FIG. 1, a metal line includes a lower Ti layer 110, a lower TiN layer 120, a conductive layer 130, an upper Ti layer 140, and an upper TiN layer 150. A height of the metal line is high and a width thereof is narrow such that a contact area between a lower insulation layer 100 and the metal layer is small. In this case, when adhesion between the lower insulation layer 100 and the metal line is not sufficient, the metal line may cant or fall on the lower insulation layer 100. In particular, as shown in FIG. 1 at 160, the metal line may cant or fall on a region wherein only an insulation layer exists in the lower layer of the metal line, without a metal layer such as a plug.
Therefore, adhesion between the lower insulation layer 100 and the metal layer should be enhanced in order to prevent canting or falling of the metal line.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.